Berlin 2014 – wissenschaftliches Programm

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SYQE: Symposium Quantum Correlations Beyond Entanglement

SYQE 1: Quantum Correlations Beyond Entanglement I

SYQE 1.4: Hauptvortrag

Dienstag, 18. März 2014, 15:30–16:00, Audimax

Quantum metrology embraced for the worst — •Gerardo Adesso — School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (UK)

Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored on the particular dynamics whose parameters are being estimated. Here we consider a novel framework where quantum estimation is performed in an interferometric configuration, using bipartite probe states prepared without full knowledge of the generating Hamiltonian. We introduce a figure of merit for the scheme, given by the worst case precision over a suitable class of Hamiltonians, and prove that it amounts exactly to a measure of quantum discord for the input probe. We demonstrate the superiority of discordant probes over classically correlated ones in a highly controllable metrology experiment with room temperature nuclear magnetic resonance, one of the paradigmatic testbeds for quantum information processing. We thus provide a rigorous operational interpretation of discord, shedding light on its potential for quantum technology.